This application is for a GEMSSTAR R03 award to provide two years of support for Dr. Dodson to establish a track record in clinical aging research. As a fellowship-trained cardiologist who has completed a training program in geriatric clinical epidemiology, the applicant is firmly committed to studying the intersection of cardiovascular disease and aging. Dr. Dodson will work under the mentorship of Dr. J. Michael Gaziano, professor at Harvard Medical School and Chief of the Division of Aging at Brigham and Women's Hospital. Dr. Mary Tinetti, professor and chair of Geriatrics at Yale University School of Medicine, and Dr. Harlan Krumholz, professor and director of the Center for Outcomes Research and Evaluation at Yale University School of Medicine, will serve as co-mentors. The award aims to combine the unique strengths of these three mentors, as well as the two institutions where the applicant has performed significant postdoctoral research. The overall goal of the proposed study is to determine the incidence rate and independent risk factors for fall-related major bleeding in a large cohort of anticoagulated older adults with atria fibrillation (AF). Over 80% of patients with AF are >65 years of age, and with the aging of the U.S. population the majority of patients with AF are expected to be aged 80 or older by 2050. Age itself is also a potent risk factor for AF-related thromboembolic stroke, and while anticoagulant therapy can reduce stroke risk by two-thirds in older adults, there is strong evidence that a considerable portion of these individuals are not prescribed anticoagulants. Clinicians repeatedly have cited concerns over fall risk and the sequelae of fall-related major bleeding as a major factor in their hesitation to prescribe anticoagulants to older adults with AF; however, we are currently lacking a precise estimate of the incidence rate of fall-related major bleeding in practice, as well as the risk factors for this outcome. The proposed study will address this gap in knowledge by developing an inception cohort of 20,000 patients with AF referred to Veterans Administration anticoagulation clinics over a 10-year time period (1/1/01- 12/31/10), and linking these data with Medicare claims data for hospitalizations for fall-related major bleeding. We hypothesize that the incidence rate of fall-related major bleeding will be more than twice the previously reported rate of 1 per 100 person-years, and that known risk factors for fall injuries (e.g. cognitive impairment, sedative use, arthritis, anemia, and prior fals) as well as covariates in the HAS-BLED model for all-cause bleeding will be independently associated with this outcome. The applicant will use knowledge generated from this study to apply for a subsequent career development award that will develop and pilot a decision-support tool for clinicians to better risk-stratify older adults with AF for fall-related major bleeding. Dring the award period, the applicant will also pursue coursework in biostatistics and epidemiology that will be applied towards an MPH degree.